This application claims the benefit of Korean Patent Application No. 1999-40645, filed on Sep. 21, 1999, the entirety of which is hereby incorporated by reference as if fully set forth herein.
1. Field of the Invention
The present invention relates to a laser cutting device for cutting a glass substrate of a liquid crystal display, and to a method of cutting such a glass substrate.
2. Discussion of the Related Art
In general, as a major component of a liquid crystal display (LCD), various glass substrates have been developed to meet different requirements, such as display type, driving systems, fabrication processes, and such. In a liquid crystal display fabrication process, the alignment and bonding of upper and lower substrates, the injecting a liquid crystal between the bonded upper and lower glass substrates, and the cutting the upper and lower glass substrates to a required size are important processes and are very closely related to device yield. A related art method for cutting the glass substrate will be explained. FIGS. 1A and 1B illustrate sections of upper and lower glass substrates that will help explain the steps of a related art method of cutting an LCD glass substrate using a diamond cutting device.
Referring to FIG. 1A, after bonding a lower substrate 10a and an upper glass substrate 10b of an LCD, the upper glass substrate 10b is cut along a cutting line A1 using a diamond cutting device, and the lower glass substrate 10a is cut along a cutting line A2. As a result, as shown in FIG. 1B, grinding of the cut surfaces is required as the cut surfaces are not smooth, as can be seen when the cutting surfaces are viewed under a magnifier. Glass particles formed in the cutting can attach to surfaces of the substrate, causing defects, Thus, a separate process for removing the glass particles is required. Damage to substrates caused by defective cuts result in poor yield, as well as a complicated fabrication process that mitigates the damage. Furthermore, it is possible that damaging static electricity can result during the grinding.
Recently, a method of cutting glass substrates using a laser beam has been suggested as an alternative to cutting with the diamond cutting device. FIGS. 2A and 2B illustrate sections of upper and lower glass substrates that will help explain the steps of cutting an LCD glass substrate by using a laser beam.
Referring to FIG. 2A, after an upper glass substrate 10b and a lower glass substrate 10a are bonded, the upper glass substrate 10b is cut along a cutting line A1 by directing a laser beam thereto from an upper side of the upper glass substrate 10b. Additionally, the lower glass substrate 10a is cut along a cutting line A2 by directing a laser beam along a cutting line A2 from a lower side of the lower glass substrate 10a. As a result, as shown in FIG. 2B, the upper and lower glass substrates 10a and 10b are cut. In this instance, though the cutting surfaces are smooth, the edges of the cutting surfaces are sharp, having almost 90xc2x0 angles. When using a TAB(Tape Automatic Bonding), or a TCP (Tape Carrier Package), grinding of the sharp edges is required as the tape is liable to be cut by the edges.
That is, a laser beam is directed to the upper substrate from above to cut the upper substrate, and a laser beam is directed to the lower substrate from underneath to cut the lower substrate. According to this, though the cut edge on the side the laser beam is directed to is rounded, the opposite edge is still approximately 90xc2x0. Accordingly, as the edge through which TAB or TCP proceeds is the edge of the lower glass substrate nearest the upper glass substrate, that edge being approximately 90xc2x0, there is still a high possibility of damage to the TAB or TCP.
Accordingly, the present invention is directed to a laser cutting device for cutting a glass substrate of a liquid crystal display, and a method for cutting a glass substrate by using the same, that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a laser cutting device for cutting a glass substrate of a liquid crystal display and that can provide a sloped cut surface suitable for use with TAB, TCP or FPC.
Another object of the present invention is to provide a method for cutting a glass substrate by using the laser cutting device that is applicable to TAB, TCP or FPC bonding of the glass substrate.
Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the laser cutting device includes a vacuum chuck rotatably mounted for securing first and second substrates which are bonded, a rotating member for rotating the vacuum chuck, and a laser oscillator for directing a laser beam to the first and second substrates in one direction for cutting the substrates held by the vacuum chuck.
In other aspect of the present invention there is provided a method for cutting a glass substrate by using a laser cutting device, including the steps of (a) securing first and second substrates, both of which are bonded, to a vacuum chuck, (b) rotating the vacuum chuck so that the bonded first and second substrates face the ground, and (c) directing a laser beam to the first and second substrates from below, to cut the substrates.
In another aspect of the present invention, there is provided a method for cutting a glass substrate by using a laser cutting device, including the steps of (a) securing first and second substrates, both of which are bonded, to a vacuum chuck, (b) directing a laser beam to the second substrate from above, to cut the second substrate, (c) rotating the vacuum chuck so that the bonded first and second substrates face the ground, and (d) directing a laser beam to the first substrate from below, to cut the first substrate.
In further aspect of the present invention, there is provided a method for cutting a glass substrate by using a laser cutting device, including the steps of (a) securing first and second substrates, both of which are bonded, to a vacuum chuck, (b) rotating the vacuum chuck with respect to the ground by an angle, and directing a laser beam toward one end portion of each of the first and second substrates to cut the one end portion of each of the first and second substrates, and (c) rotating the vacuum chuck in an opposite direction with respect to the ground, and directing the laser beam to the other end portions of the first and second substrates, to cut the other end portions of the first and second substrates.
Preferably, the bonded first and second substrate are rotated to face the ground with an angle, and the laser beam is directed thereto from below, when the laser is directed in a vertical direction.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.